Whether you go hard-wired or plug-in, it would be handy but not required to have a circuit shut-off somewhere near the charging unit. When I had my L2 unit installed in the garage back in late 2011, the distance to the controlling circuit breakers in the load center was quite far and the electrician suggested the shut-off. As it turned out, this became very handy as I had a unit that failed and was replaced under warranty. The ability to shut down the circuit without having to run to a distant load center made removal of the old unit, installation of the new one, and various testing to be done quickly and easily.
Where I live now, I have the L2 unit about 15 feet from the relevant load center in the garage so no additional shut-off is needed. Since your installation is a good ways and two floors from the EVSE, a close-by shut-off could be very handy.
Good luck with your solution, and update the forum with results and pictures please!
2012 SL Super Black
12,900 miles, 10 bars showing, 75% SOH, 49.80 Ahr
Model 3 - Long Range, Premium Upgrade, Extended AutoPilot, Full Self-Driving, 15 miles on odo
Delivered: July 19, 2018
Ecstatic-ness began: July 19, 2018